Ambient Dust Sampling Protocol Near WTC, Oct 2001

NYC 9/11 Public Portal Document

V. Residence Selection/Sampling Rationale

The selection of residential sampling locations will be decided upon by NYC DOH. The NYCDOH approach is described as follows: Approximately 60 residential units will be sampled. A series of three concentric circles is being drawn around the WTC location. These circles will be divided into North, South, and East transects. Approximately three residential buildings will be selected for testing from within each area.

Testing locations will mainly focused on occupied residences. However, approximately five unoccupied units nearest the WTC will be targeted for testing. In addition, approximately ten units will be selected outside of the concentric circles, in neighboring boroughs, to serve as background sample locations.

It should be noted that contaminant/materials of concern may vary as the distance of the residence increases from the WTC.

All samples collected, unless analyzed using destructive methods, will be archived until further notice.

VL Sampling/Analysis Approach:

1. Interior Air and dust sampling will focus on both common/high traffic areas of the building (e.g., lobbies, front entryways) and.on a selected number of apartments/units in the building. Attempts will be made to select apartments/units where visible dust is and is not reported. Selecting entryways and common areas should be representative of worst case conditions for contaminant/material track­ in from outdoors. Selecting apartments/units in the same building should provide information the ranges found in indoor living spaces.

If the building is unoccupied, aggressive (leaf blower, high-power fan) indoor air sampling should be conducted. If the building is occupied, air sampling should be conducted with the building/unit HVAC system in continuous operation. After sampling is completed, filters for the HVAC system, if applicable, should be inspected. If dust is present, recommend filter replacement.

Indoor air sampling for asbestos will be conducted and analyzed using NIOSH method 7400. If an action level is exceeded subsequent filter analysis using NIOSH 7402 to determine if the fibers present are asbestos. Respirable crystalline silica will be sampled and analyzed using NIOSH method 7500. Air sampling for inhalable, thoracic, and respirable size particles will be conducted using the lOM sampler. The relative amounts (percent weight) of each fraction present will be determined. Each fraction will be analyzed for silica, gypsum, mica, fiberglass, and calcite using XRD.

Indoor floor dust samples will be collected using EPA’s Environmental Response Team (ERT) SOP for household dust collection (attached). As much dust as possible will be collected; the area vacuumed will be measured and reported. Samples will be analyzed for asbestos, crystalline silica, gypsum, mica, fiberglass and calcite using XRD. The pH of the dust will be tested using

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